Abstract: | Masir N, Jones M, Lee A M, Goff L K, Clear A J, Lister A, Marafioti T & Mason D Y (2010) Histopathology 56 , 617–626 The expression of Bcl‐2 by proliferating cells varies in different categories of B‐cell lymphoma Aims: To investigate the relationship between Bcl‐2 protein expression and cell proliferation at single‐cell level in B‐cell lymphomas using double‐labelling techniques. Methods and results: The relationship between Bcl‐2 protein expression and cell proliferation was explored in 124 cases of B‐cell lymphoma using double immunofluorescence labelling for Bcl‐2 and Ki67. In follicular lymphoma, marginal zone lymphoma and a subset of chronic lymphocytic leukaemia/small lymphocytic lymphoma (CLL/SLL), neoplastic cells tended to lose Bcl‐2 when they are in cell cycle. This pattern is usually maintained in both follicular lymphoma and CLL/SLL when they undergo high‐grade transformation. In mantle cell lymphoma, diffuse large B‐cell lymphoma and a subset of CLL/SLL, the inverse relationship (between Bcl‐2 and Ki67) was not observed, i.e. the proliferating cells tended to show co‐expression of Bcl‐2. Conclusions: In low‐grade lymphomas, including those that are transformed, Bcl‐2 expression is lost when cell proliferate. However, in more aggressive tumours (i.e. mantle cell and de novo diffuse large B‐cell lymphomas) the inverse Bcl‐2/Ki67 relationship was not observed. It would be of interest to explore the clinical implications in lymphoma of the presence and absence of the inverse Bcl‐2/Ki67 pattern. |